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Fungal Antigen (Serum) – Quantitative

Published: August 9, 2026Updated: August 16, 2026

This test measures the presence of fungal antigens in your blood, which can help detect infections caused by certain fungi like Cryptococcus or Blastomyces.

Quick summary

["Detecting fungal infections early can improve treatment outcomes and reduce complications."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
42804-5
Short code
Fungus Islt
Synonyms
Fungus Islt
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

The test looks for specific fungal antigens in your serum. These antigens are proteins released by certain types of fungi during an active infection. The presence of these antigens suggests an ongoing fungal infection, which may not always show up on other tests like blood cultures or imaging studies.

Why It’s Done

Your healthcare provider may order this test if you have symptoms like fever, weight loss, or persistent cough, especially if you live in or travel to areas with higher fungal infection risks. It’s also used in people with weakened immune systems (e.g., due to HIV, chemotherapy, or organ transplants) who are at higher risk for fungal infections.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw blood. It usually takes a few minutes, and you may feel a slight pinch. If you’re on blood thinners, let your provider know before the test.

What to Expect During the Test

The blood sample is sent to a lab where it’s analyzed for fungal antigens using a sensitive immunoassay method. Results are typically available within 24 to 48 hours.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Fungal Blood Test

Frequently asked questions

How long does it take to get the results of this test?
Results are usually ready within 24 to 48 hours after the blood sample is processed. Your healthcare provider will discuss the results with you during your follow-up visit.
Can I eat or drink anything before this test?
No special diet or fasting is required for this test. You can eat and drink normally before your blood draw.
Is there any risk or discomfort associated with this test?
The most common discomfort is a slight pinch or bruising at the injection site. Rarely, there may be mild swelling or bleeding. If you’re on blood thinners, let your provider know to minimize risks.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy